I’ve recently moved onto the Omnipod (from MDI) and I’m trying to get my head around extending the bolus, and what that actually looks like on a graph.
Take the Achilles’ heel of many diabetics, the humble pizza. On MDI I would inject about 60% of my bolus before I eat, and then about an hour later I would inject the remaining 40%. It wasn’t perfect, but it avoid most of my highs and kept me in range.
The Omnipod, like all pumps, has an extended bolus feature, but from what I can gather, it behaves a bit differently than say a dual wave or a square wave on other makes of pump, and I can’t quite get my head around what it looks like.
Let’s say for my pizza I needed to take 10u (simply because it’s an easy number to work with, its not my actual I:C ratio). On MDI I would take 6u with food, 4u an hour later. With Omnipod though it looks as though if I took my 6u upfront, then extended the bolus for the remaining 4u it would slowly drip those 4u into me over the following time I’d selected. In this example, let’s say I do this over 2 hours.
Its this bit I can’t get my head around. It feels as though the extension is more like a temporary increased basal for those 2 hours, rather than more of a split like on MDI. The graphs I’ve seen of dual/square wave delivery look more like you would expect with MDI too - two peaks an hour apart with the insulin tailing off over the following 4 hours.
Can anyone explain to me in relatively simple terms, and preferably with graphs, what an extended bolus does and looks like with Omnipod?
That’s it exactly. It’s what Medtronic calls a dual wave and Animas called a combo (I think). Yes, you get the same thing from a temp basal, but it’s fewer button pushes.
I’m not sure if any pump on the market gives a delayed second bolus – though it’s a feature many of us would like. But there’s always an alarm clock if you prefer MDI-style double or triple bolusing.
Simple terms with graphs – the “Combination bolus” graph is the Omnipod extended bolus:
This thread has some explanations on it, starting here. Basically, all pumps do their extended the same way. They just use different names. They are all the exact same. And yes, if you want to think of an extended as an increase in basal, it is the all the same to your body. It is not the same as doing two shots.
You could do two boluses instead if you wanted to. All kinds of ways to do it. The problem with doing the second bolus is just if you forget.
Anyway, check out this thread and then let me know if you have questions. Happy to answer for you.
Great! Thank you folks, that’s starting to make a lot more sense to me now.
Out of interest, and I know YDMV applies here, what do you personally do for pizza? 50% then extend for 3 hours? All at once? Extend the whole thing over 3, 4, 5+ hours?
I’ve got lots of learning to do on how to deliver insulin now I’m pumping, and it’s taking a while to “unlearn” all of my MDI knowledge.
It depends on the pizza – how much cheese and meat there is, how thick the crust is – and of course it depends how much you eat.
Depending on how much fat and meat there is on my pizza, I’ve used anything from 50/50 over 5 hours, 70/30 over 4 hours, to 30/70 over 3 hours, with the larger amount for the extended if it’s high-fat/protein. If I have one slice (or several slices of a low-fat/low-protein pizza), then it’s just a normal bolus.
These formulas also work for other high-fat/protein/carb meals like mac and cheese or pasta with a creamy sauce like Alfredo. And trifle with custard and cream.
You’ll need to experiment to find what works for you. You could start with 50/50 over 4 hours, then keep an eye on your CGM for the next 4 to 8 hours and see what adjustments you might want to make for next time.
I’ve also found that what worked one time won’t necessarily work another time, even if it’s the same kind of pizza. One ratio worked for me for years, and then suddenly didn’t.
What we have found is that every pizza is different. Have a good starting place established for generic pizza and then adjust until you find nirvana. We have three pizza places we eat at regularly, and each one has a different solution. My son currently can nail Costco Pizza, a local joint, and shudder Domino’s since his friends eat that every week.
It’s a temp basal. I used to use the extended bolus to account for protein/fat but I’ve given up on that and now I just use the temp basal. The result is the same but I just find setting a higher basal rate easier to control than guesstimating the carbohydrate equivalent of a high protein/fat intake (e.g. nuts).
Except, of course, that you can also set a temp basal Because a temp basal and an extended bolus simply change the duration between the 0.05IU insulin pulses the pump delivers they are exactly equivalent, at least on the Omnipod, where the extended bolus is delivered at a constant rate over the duration. The temp basal can run for 12 hours while the extended basal is limited to 8 hours, but if you want two extended boluses it is possible so long as one of them is 8 hours or less.
Because a temp basal and an extended bolus simply change the duration between the 0.05IU insulin pulses the pump delivers they are exactly equivalent, at least on the Omnipod, where the extended bolus is delivered at a constant rate over the duration. The temp basal can run for 12 hours while the extended basal is limited to 8 hours, but if you want two extended boluses it is possible so long as one of them is 8 hours or less.